Safety and arming mechanism



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SAFETY AND ARMING MECHANISM Filed Aug. 31, 1959 4 Sheets-Sheet 4 INVENTOR 90mm m mm J-Iwwey a. 301m United States Patent 3,415,191 SAFETY AND ARMING MECHANISM James M. Meek, Silver Spring, Md., James J. Charuhas,

Washington, D.C., and Harvey A. Foure, Landover,

Md., assignors to the United States of America as represented by the Secretary of the Army Filed Aug. 31, 1959, Ser. No. 837,291 3 Claims. (Cl. 102-78) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to use of any royalty thereon.

This invention relates to an arming system for use in air-to-air guided missiles.

Safety considerations for arming systems which are to be used in air-to-air guided missiles require first, that the arming system not arm upon failure of any critical part, and second, that arming occur only after the missile experiences some minimum sustained axial acceleration for some minimum time, and also travels some predetermined distance from the launching aircraft.

In the present invention, two arming trains coact to insure that arming occurs only after the missile has travelled a predetermined distance through the air with sustained axial acceleration for some predetermined minimum time. This is because one arming train is adapted to move to arm the missile only in response to sustained acceleration for a minimum time, while the other arming train is adapted to move to arm the missile as a result of the missile traveling a predetermined distance through the air. The trains are operatively connected in series so that if the missile decelerates as a result of premature missile burn-out and yet travels the predetermined distance through air, the arming train which requires sustained acceleration before it allows the missile to arm will prevent arming.

An important feature of this invention is in providing that the two arming trains be connected by a virtually frictionless linkage. The feature is important because air-to-air guided missiles may undergo sharp changes in flight direction when fired at an air target in order to overcome evasive target maneuvers. These sharp changes in flight direction cause large transverse accelerations to be developed which may interfere with the operation of the arming system. Known prior art arming systems which utilize movement of axial acceleration-responsive weight elements to arm the system, either will not function at all under these conditions, or undesirable stored energy devices must be incorporated in the design in order to make them function accurately. As a result, it has been found that known prior art systems which are designed to arm the missile after it has travelled a predetermined distance through the air do not arm the missile at constant distances when the missile undergoes sharp changes in flight direction. Consequently, the distance at which arming actually occurs is oftentimes farther from the launching aircraft than desired, and in some cases the missile may not be armed when it reaches the target.

According to this invention the above-mentioned problems are overcome by providing two weights responsive to axial acceleration which are interlocked, one of these weights moving to unlock a detonator for rotation to an armed position as a result of sustained axial missile acceleration, and the other unlocking the detonator for rotation to an armed position as a result of the missile travelling a predetermined distance through the air. The two axial acceleration-responsive weights are connected together by a linkage which permits the detonator to rotate to an armed position only when both accelerationresponsive weights have moved a predetermined amount in response to axial missile acceleration, regardless of large transverse accelerative forces which might be devel- 3,415,191 Patented Dec. 10, 1968 oped due to sharp changes in the flight direction of the missile.

The specific nature of the invention, as well as other objects. uses and advantages thereof, will clearly appear from the following description and from the aceompany ing drawing, in which:

FIG. 1 is a pictorial view of the forward section of the arming system of this invention, showing only those essential elements which comprise the system.

FIG. 1a is a pictorial view of the middle section of the arming system of this invention showing only the essential elements comprising the system.

FIG. 1b is a pictorial view of the rearward section of the arming system of this invention showing only the essential elements comprising the system.

FIG. 2 is a pictorial view of a portion of the forward section shown in FIGS. 1 and 1a.

FIG. 3 is a pictorial view of the escapement train which restrains movement of one of the acceleration-responsive weig-hts so that displacement of the weight substantially represents proportional distances travelled by the missile through air.

FIG. 4 is a detailed sectional side view of the rearward and a portion of the middle sections of the arming system of this invention.

FIG. 4a is a detailed sectional side view of the forward and a portion of the middle sections of the arming system of this invention.

FIG. 5 is a complete side sectional view of the safety and arming mechanism of this invention.

FIGS. 1, 1a and 1b are pictorial views with certain parts cut away in order to more clearly describe the arming system 10 of this invention. Arming system 10 is positioned with the longitudinal axis of the system parallel to the longitudinal axis of the missile in which the system 10 is incorporated. Solenoid 11 comprises the forwardmost part of system 10 and is positioned in the forward end of the missile, while rotor 72 constitutes the rearwardmost part of arming system 10. Arming system 10 is suitably encased in a cylindrical sleeve 87 FIG. 4).

Wires 12 electrically connected solenoid 11 to a circuit (not shown) which energizes solenoid 11 when the missile is launched. Solenoid energization circuits are well known to those skilled in the art, and may readily be provided. Shaft 13 is driven by solenoid 11 and is provided with a cam 14 which has a beveled edge 15. Edge 15 is designed to ride against roller 16 which is rota-tably mounted to shaft 17, the latter being fixed to the forward end 18 of lever 19. Lever 19 is pivotally mounted to encasing sleeve 87 by means of pin 20.

The rearward end 21 of lever 19 has afiixed thereto, by any suitable means such as a rivet 95, a bent leaf spring 96. Spring 96 is bent upwardly, as shown, so that upper end 97 can ride against bracket 24. Bracket 24 is fixed to the encasing sleeve 87 and extends inwardly from the encasing sleeve to provide *a surface against which upper end 89 can slide when lever end 21 is pivoted. Rearward end 21 of lever 19 fits into lower oval slot 25 in lock plate 26. Lock plate 26 is also provided with an upper oval slot 27 and a rectangular slot 28 which communicates with oval shot 27. Upper oval slot 27 is tapered as shown by numeral 27a.

The width of rectangular slot 28 is smaller than the outer diameter of cylindrical shaft 29 of lock bolt 30 so that shaft 29 cannot pass upwardly through slot 28. Lock bolt 30 comprises the shaft 29, an arrow-shaped forward end 31 and a rearward end 33. The width of the base 32 of end 31 is considerably greater than the width of slot 28 so that the end 31 and lock bolt 30 cannot pass rearwardly in an axial direction through slot 28. Oval slot 27, however, is of greater width than the base 32 of end 31,

and therefore end 31 can pass rearwardly through slot 27. As a result, when slot 27 is moved upwardly by end 21 of lever 19 a distance sutficient to align slot 27 and end 31. lock bolt 30 will be free to move rearwardly in a direction parallel to the longitudinal axis of shaft 29, that is. in the direction of arrow A.

Oval slot 27 and slot 28 are tapered as shown by numeral 27a (FIGS. 1 and 4a). The function of the tapered surface 27a will be discussed subsequently.

Pin 34 is fixed to the rearward end 33 of lock bolt 30, and extends to contact the coils of coil spring 35. Two additional pins (not shown) are fixed to G-weight 39 and are positioned at 120 degree angles with respect to pin 34 around the periphery of the forward coil 36a of spring 35. The rearward coil 36 of coil spring 35 abuts the forward edge 37 of cylindrical collar 38. When lock bolt 30 is held in slot 28, coil spring 35 will be under no significant tension or compression. Therefore, the arming system does not have any stored spring energy which could cause premature arming should any part in the system fail.

Pin 34 also serves to fix lock bolt to G-weight 39. G-weight 39 is positioned between G-weight shaft 40 and coil spring 35. Although a portion of G-weight 39 has been cut away as shown in FIG. 1a, the outer surface of G-weight 39 is cylindrical as shown in FIG. 4a, and is housed completely inside encasing sleeve 87. The encasing sleeve 87 (FIG. 4a) has a longitudinal slot for movement of pins 34, 34a and a third pin (not shown) therethrough. Sleeve 87 is positioned between the coil spring and the outer surface of G-weight 39 for the purpose of guiding rearward movement of G-weight 39. One side of the slot in encasing sleeve 87 is defined by surface 88 cut longitudinally from sleeve 87. G-weight 39 has an inner annular shoulder 41 which is abutted by cylindrical flange 42 on enlarged G-weight shaft section 43. An inner cylindrical surface 44 is provided in G-weight 39 which is spaced from the surface of cylindrical section 43.

G-weight shaft consists of equi-diametered shaft sections 40a, 40b, 40c, 40d, enlarged cylindrical sections 43 and 56, a threaded portion 73 and a reduced diametered shaft section 75. G-weight shaft 40, like G-weight 39 moves axially rearward when subjected to forces of acceleration produced by missile flight. Anti-friction bearings 90 and 90a (FIGS. 4 and 4a) are used to provide additional support to the ends of shaft 40. Since flange 42 abuts shoulder 41 on G-weight 39, shaft 40 will not move rearwardly unless G-weight 39 has moved rearwardly in response to acceleration. The surface 86 between the rearward end of enlarged shaft section 43 and section 4% is tapered so that there is a smooth continuous surface between enlarged section 43 and shaft section 40b upon which roller 52 can ride.

Lever 49 (FIG. 1a) is mounted for pivotal movement by means of pin 50 to fixed bracket 51. Bracket 51 is fixed to the inner walls of the encasing cylinder 87 (FIG. 4). Lever 49 has two rollers 52 and 53 which are rotatably mounted to the forward end 54 and rearward end 54a, respectively, of lever 49. Positioned between rollers 52 and 53 is a bearing 55 which is fixed to lever 49. Bearing 55 slides along the outer periphery of enlarged shaft section 56 on G-weight shaft 40 when shaft 40 moves rearwardly. When roller 52 engages shaft section 4%, and bearing 55 engages shaft section 56, no pivotal movement of lever 49 is possible because roller 52 and bearing 55 are positioned on opposite sides of pin 50 upon which lever 49 pivots.

Catch 47 is fixed to the forward end 54 of lever 49 below, and spaced from roller 52 and thus can pivot about pin 50 with lever 49. The rearward end of G-weight 39 has a fiat surface 45. Hook end 46 of catch 47 is positioned above surface 45 and therefore will not contact weight 39 when weight 39 moves rearwardly in response to forces of acceleration. Slot 58 is formed in weight 39 and is adapted to receive the hook. and 4. of catch 47 when slot 58 moves under catch 47 as a result of weight 39 moving rearwardly.

The rearward end of G-weight 39 (FIG. 1a) is provided with a rectangular longitudinal slot, one side of which is defined by surface 139. The slot so provided extends the length of weight 39 and permits G-weight 39 to move rearwardly past bracket 51 (FIGS. 1 and 4) and pin 60. Surface 139 and surface 88 are substantially aligned (FIG. 4). G-weight 39 can therefore move rearwardly in the direction of arrow A until G-weight end 39a abuts shoulder 89 formed in encasing sleeve 87 (FIG. 4). When the arming system 10 is subjected to setback as a result of missile launching, G-weight 39 will instantaneously move rearwardly and abut shoulder 89. When G-weight 39 abuts shoulder 89, slot 58 will be positioned under catch 47. Upon clockwise rotation catch 47, hook end 46 will engage slot 58 thereby preventing foreward movement of G-weight 39.

Roller 53 engages the upper end 62 of pin 60 to lock pin 60 against rearward movement. The lower end 61 of pin 60 abuts the rearward edge 62 of collar 38. Pin 60 1s fixed to the forward end 63 of the shaft 64. Pin 60 engages both collar 38 and shaft 64 and hence provides a connection between these two parts. When the arming system 10 is in the unarmed position as shown in FIGS. 1, la and 1b roller 53 locks shaft 64 against rearward movement because it engages the upper end 62 of pin 60. Thus even though the collar 38 should be urged rearwardly by compression of coil spring 35, roller 53 engaging pin 60 will prevent rearward movement of collar 38 and shaft 64.

The forwardrnost end of G-weight shaft 40 is threaded as indicated by numeral 73 (FIG. 1). Pinion 74 meshes with threaded portion 73 and is geared, as shown in detail in FIG. 3, to a conventional type of escapement mechanism 84. Escapement mechanism 84 is of the type which restrains movement of shaft 40 in response to acceleration so that shaft 40 moves rearwardly a distance which is proportional to the distance traveled by the missile. This type of escapement mechanism is well known to those skilled in the art as a double integrator because it substantially converts the acceleration of the shaft 40 to an axial movement which is proportional to the distance traveled by the missile. If desired, a second escapement mechanism can also be geared to threaded portion 73 in order to provide additional safety should there be a failure in the gearing of escapement mechanism 84.

Shaft 64 has a pin 65 affixed thereto and a sleeve 66 which is rotatable on shaft 64. Gear 67 is fixed to the rearward end of sleeve 66 and rotates with sleeve 66. Sleeve 66 is driven counterclockwise by means of pin 65 moving through slot 68 formed in sleeve 66. y

The end of shaft 64 consists of shaft section 69 of reduced diameter and a cylinder 70. Cylinder 70 fits into cylindrical opening 71 but has a diameter which is considerably larger than the width of slot which communicates with opening 71 so that when cylinder 70 is in opening 71 and aligned with slot 80, rotation of rotor 72 in a clockwise direction is prevented. Rotor 72 houses a detonator 91 (FIG. 4) which is aligned with a primer charge 92 when rotor 72 rotates clockwise ninety degrees. Until rotor 72 rotates clockwise, the arming system 10 will remain unarmed because the detonator 91 carried by the rotor 72 will be ninety degrees out-of-line with primer charge 92.

Clot 80a in rotor 72 has a width which is larger than the diameter of cylinder 70. Slot 80 has a width which is larger than the diameter of shaft section 69. When shaft 64 is moved axially rearward a distance sulficient to cause cylinder 70 to move from opening 71 into slot 80a, shaft section 69 will move into opening 71 and align with slot 80. Rotor 72 will then be unlocked for clockwise rotation for the requisite ninety degrees which causes the detonator in rotor 72 to align with the main explosive train.

Between shaft sections 406 and 40d is reduced-diameter shaft section 75. Shaft section 40d engages arcuate l 76 in locking cylinder 77. Locking cylinder 77 is fixed to shaft 78 which also has rotor 72, switch 79 and a gear 81 fixed thereto. Cylinder 77 locks shaft 78 against rotation when section 40d is opposite arcuate slot 76, as shown in FIG. 1b. Arming switch 79 is a conventional rotary arming switch which is designed to close certain contacts upon clockwise rotation of shaft 78 through an angle of ninety degrees. Lead wires 82 extending from switch 79 are connected to the detonator 91 housed in rotor 72 and to conventional means (not shown) which can energize and thereby fire the detonator 91 when the missile impacts with the target. Upon clockwise rotation of shaft 78 through ninety degrees, certain contacts in switch 79 will close causing the detonator 91 to be electrically connected to some suitable initiating means, such as a piezoelectric crystal, which can electrically energize and initiate detonation of the detonator 91 in rotor 72 when the crystal impacts with the target. The ninety degree angle of rotation required of shaft 78, before certain contacts in switch 77 are closed is the same angle as that required before the detonator in rotor 72 is rotated by shaft 78 to an in-line position with the primer charge 92, so that when the detonator 91 is fired, the main explosive train to the missile warhead (not shown) will be initiated by the primer charge 92.

However, rotation of shaft 78 is prevented while section 40d is opposite arcuate slot 76. When shaft section 75 is moved to a position opposite locking cylinder 77 by rearward movement of shaft 40, locking cylinder 77 will be free to rotate because cylinder 77 will not contact the reduced diameter of shaft section 75. It will be evident that until G-weight shaft 40 moves rearwardly a distance sutficient to move shaft section 75 opposite cylinder 77, shaft section 40d -will prevent arming of the missile by preventing rotation of shaft 78 and gear 79.

The operation of arming system is summarized as follows. When the missile in which arming system 10 is incorporated is fired, the operator by pressing the trigger to launch the missile closes a switch hwich connects wires 12 to a source of electrical energy. As a result, solenoid 11 is electrically energized at the same time the missile is launched.

Solenoid 11 thereupon rotates shaft 13 and cam 14 which forces roller 16 downwards. Cam 14 is designed such that the beveled edge remains in contact with roller 16 during energization of solenoid 11. Since lever 19 is pivoted on pin 20 which is fixed to encasing sleeve 87, rearward end 21 of lever 19 will move upwards against the resilience of spring 96. As a result, end 21 pushes lock plate 26 upwards until upper oval slot 27 is moved opposite base 32 of lock bolt 30.

When the missile in which arming system 10 is incorporated is launched, setback causes G-weight 39 to move virtually instantaneously with high acceleration in the direction of arrow A. Rearward movement of G- weight 39 is guided by the inner walls 87a of encasing sleeve 87 (FIG. 4) and is prevented by lock bolt 30 when lock bolt 30 is held by rectangular slot 28 in latch lock 26. When latch lock 26 is moved upwardly by lever 19, slot 27 will be moved opposite base 32 of bolt 30. Since slot 27 is wide enough for base 32 to pass therethrough, bolt 30 will be released by latch lock 26. The release of bolt 30 allows G-weight 39 to move rearwardly at high acceleration from the initial position shown in FIGS 1 and 4a, until G-weight end 39 abuts shoulder 89 in encasing sleeve 87.

Pin 34, pin 34a and another pin (not shown) are fixed to the forward end of G-weight 39 at angles of 120 degrees with respect to pins 34 so that when G-weight 39 moves rearwardly at high acceleration these pins will act equally to compress coil spring 35 against forward edge 37 of cylindrical collar 38. Cylindrical collar 38 cannot move rearwardly because roller 53 engages pin 60 which abuts the rearward edge of collar 38. Since roller 53 is rotatab ly mounted to lever 49 which is pivotally fixed by means of bracket 51 to the encasing sleeve 87, roller 53 can only pivot about pin 50 and cannot be forced rearwardly by spring 35.

Rearward movement of G-weight 39 causes shoulder 41 to move from contact with flange 42 on enlarged cylindrical section 43. G-Weig'ht shaft 40 is thereby released to move rearwardly under the forces of acceleration produced by acceleration of the missile. Rearward movement of G-weight shaft 40 is restrained by pinion 74 meshing with threaded portion 73. As discussed above, escapement mechanism 84 to which pinion 74 is geared limits axial movement of shaft 40 so that under constant missile acceleration the distance traveled by shaft 40 in a rearward direction is proportional to the distance traveled by the missile through the air.

As mentioned above, sustained setback produced by missile launching cases G-Weight 39 to move rapidly rearward until end 39a abuts shoulder 89. Concurrently, solenoid 11 will be deenergized by the opening of a suitable switch which is driven by a timer (not shown) which is initiated by the launching of the missile. Such a system is well known to those skilled in the art. As a result of deenergizing solenoid 11, spring 96 will flex and restore latch lock 26 to the position shown in FIGS. 1a and 4a. Cam 14 and shaft 13 will, of course, be freely rotatable in solenoid 11 since the solenoid is deenergized. End 31 of bolt 30 will previously have travelled rearwardly through upper oval slot 27 as a result of G-Weight 39 responding to forces of acceleration.

Should the missile decelerate prematurely during launching, coil spring 35 will expand pushing end 31 of bolt 30 forward and against tapered surface 27a formed in slot 28 and in oval slot 27. Tapered surface 27a guides arrow-shaped end 31 and shaft 29 upwardly into slot 28 so that base 32 will be restored to its position and relatched in slot 28, as shown in FIG. 1, thereby preventing rearward movement of bolt 30. The system 10 will thereupon be locked against arming and the missile is dudded as a result.

Upon sustained setback, weight 39 will move rearwardly guided by the inner walls 87a of sleeve 87, a distance sufficient for slot 58 to move under catch 47. Further rearward movement of G-weight 39 is prevented by G-weight end 39a abuttting shoulder 89. Catch 47 is prevented from pivoting downward into slot 58 because fixed bearing 55 would ride against enlarged cylindrical section 56 preventing clockwise rotation of lever 49. Normally a clearance exists between the bearing 55 and the cylindrical section 56 due to the spring force acting through collar 38, pin 60 and shaft 64 against roller 53. After the missile has traveled a predetermined distance through the air, shaft 40 will have moved from its initial position rearwardly a distance proportional to the square root of sustained acceleration. The distance which G- weight shaft 40 must move before arming will occur is the length of shaft section 40d, because reduced-diameter shaft section must be opposite locking cylinder 77 before arming can occur. When G-weight shaft 40 moves rearwardly a distance which is slightly less than the length of shaft section 40d, roller 52 will begin to ride upon tapered surface 86 while bearing 55 will be ovenlapping the edge between enlarged cylindrical section 56 and shaft section 40b. Further rearward movement of shaft 40 to its final position will result in bearing 55 riding off enlarged cylindrical] section 56 while roller 52 rides over tapered surface 86 and upon enlarged cylindrical section 43. When roller 52 rides upon enlarged cylindrical section 43, catch 47 connected to lever 49 will be driven clockwise about pin 50 and enter slot 58 which has moved rearwardly with G-weight 39. Bearing 55 will allow clockwise pivotal movement of catch 47 because shaft section 4%, having a smaller diameter than section 56, will now be over bearing 55. Clockwise rotation of lever 49 also causes roller 53 to disengage from contact with upper end 62 of pin 60.

At this time shaft section 75 is opposite loc'king cylinder 77. Further rearward movement of shaft 40 is prevented by flange 42 again abutting shoulder 41 of G- weight 39. This is the final position of G-weight shaft 40 and G-weight 39.

When roller 53 disengages from pin 60, collar 38 is released and moves rearwardly as a result of pressure exerted by coil spring 35. Coil spring 35 expanding against collar 38 drives collar 38 rearwardly over cylindrical outer wall 87b of encasing sleeve 87. Forward movement of G-weight 39 will not occur because of setback acting on G-weight 39, and after missile acceleration ceases, forward movement of weight 39 will not occur because slot 58 is held by hook end 46 of catch 47, catch 47 having been forced into slot 58 by clockwise rotation of lever 49. Therefore, during and after missile acceleration coil spring 35 can only expand rearwardly.

Rearward expansion of coil spring 35 against collar 38 drives pin 60 and shaft 64 rearward. Rearward movement of shaft 64 drives cylinder 70 from opening 71 and into alignment with slot 80a. Shaft section 69 will also move rearwardly and align with slot 80. Thus rearward movement of shaft 64 unlocks rotor 72 for clockwise rotation to the armed position.

Rearward movement of shaft 64 also drives pin 65 through slot 68 in sleeve 66, thereby driving gear 81 counterclockwise as shown by the arrow. Gear 81 rotates shaft 78 clockwise because reduced-diameter shaft section 75 is now opposite locking cylinder 77. Clockwise rotation of shaft 78 causes rotor 72 to align detonator 91 with primer charge 92, and rotates arming switch 79 so that the circuit between the detonator 91 and the means which initiates detonation of the detonator is closed. As a result the missile is armed.

It will be apparent to those skilled in the art that G- weight 39 and shaft 64 cooperate to form one mechanical arming train which unlocks rotor 72 for rotation to the armed position, while G-shaft 40 and shaft 78 cooperate to form a second mechanical arming train which also unlocks rotor 72 for rotation to the armed position. Both mechanical trains must function in order to arm the missile. Thus a failure in any part of either train would not prevent the other train from locking rotor 72 against rotation to the armed position.

Flange 42 abutting annular shoulder 41 prevents G- shaft 40 from unlocking shaft 78 and rotor 72 unless G- weight 39 has moved rearwardly a predetermined distance in response to sustained setback. Thus flange 42 interlocks the mechanical arming train of G-shaft 40 with the train of G-weight 39. As a result, unless the missile experiences sustained setback arming will not occur regardless of the distance travelled by the missile through the air. Only when the missile experience sustained setback and travels a predetermined distance through the air will both arming trains unlock rotor 72 for rotation to the armed position.

Since G-weight 39 moves rapidly rearward when subjected to sustained forces of setback produced by launching of the missile, immediately after the missile is launched G-weight 39 will move to its final position where end 39:: abuts shoulder 89 on encasing sleeve 87. As a result, when the missile is operating at high maneuver, which produces high transverse side thrusts, the only G-weight which will be required to move rearwardly will be G-shaft 40. The arming rotor 72 and multiple switches 79 are also designed to operate during high transverse side thrust conditions.

It will be evident to those skilled in the art that G-shaft 40 and the associated lever 49 are so designed and connected by rollers and bearings that G-shaft 40 can move rearwardly to arm the system 10 in response to sustained acceleration with a minimum of frictional resistance.

An arming system built in accordance with the abovedescribed invention was found to operate properly even when the acceleration forces acting transversely of the missile axis were twice the magnitude of the axial acceleration forces. Known prior art arming systems have not been able to operate properly under such conditions.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

We claim as our invention:

1. A safety and arming mechanism, comprising first and second G-weights movable in the same direction from an initial to a final position, a coil spring substantially enclosing both G-weights, said spring having two ends, means for preventing expansive movement of one end of said spring connected to said second G-Weight and compressing said spring as a result of movement of said second G-weight towards said final position, a catch member engaging said first G-weight for releasing the other end of said spring, said member releasing said other end of said spring as a result of movement of said first G- weight to said final position, and detonator means connected to said other end of said spring and movable to an armed position as a result of spring expansion.

2. A safety and arming mechanism, comprising first and second G-weights movable in the same direction from an initial to a final position, said first G-weight being substantially cylindrical, a coil spring substantially enclosing both G-weights, said spring having first and second ends, means for preventing expansive movement of the first end of said spring connected to said second G- weight and compressing said spring as a result of movement of said second G-weight towards said final position, a catch element pivotally mounted to said mechanism between said G-weights, said catch having two ends, one end of said catch riding upon the surface of said first G-weight during movement of said first G-weight and the other end holding the second end of said spring against expansive movement thereof, means for tripping said one end of said catch extending from said first G-wcight, said catch releasing said second end of said spring for expansive movement as a result of movement of said first G-weight towards said final position, and detonator means connected to said second end of said spring and movable to an armed position as a result of spring expansion.

3. The safety and arming mechanism as claimed in claim 2, wherein said second G-weight is substantially cylindrical and said G-weights are mounted substantially parallel to each other.

References Cited UNITED STATES PATENTS 2,915,013 12/1959 Moorhead 10270.2 2,486,362 10/1949 OBrien 102-70.2 2,537,953 l/l951 Andrews l0278 2,586,437 2/1952 Rabinow 102--78 2,836,118 5/1958 Hjelm l0278 X 2,863,393 12/1958 Shelley 10278 SAMUEL FEINBERG, Primary Examiner.

GERALD H. GLANZMAN, Assistant Examiner. 

1. A SAFETY AND ARMING MECHANISM, COMPRISING FIRST AND SECOND G-WEIGHTS MOVABLE IN THE SAME DIRECTION FROM AN INITIAL TO A FINAL POSITION, A COIL SPRING SUBSTANTIALLY ENCLOSING BOTH G-WEIGHTS, AND SPRING HAVING TWO ENDS, MEANS FOR PREVENTING EXPANSIVE MOVEMENT OF ONE END OF SAID SPRING CONNECTED TO SAID SECOND G-WEIGHT AND COMPRESSING SAID SPRING AS A RESULT OF MOVEMENT OF SAID SECOND G-WEIGHT TOWARDS SAID FINAL POSITION, A CATCH MEMBER ENGAGING SAID FIRST G-WEIGHT FOR RELEASING THE OTHER END OF SAID SPRING, SAID MEMBER RELEASING SAID OTHER END OF SAID SPRING AS A RESULT OF MOVEMENT OF SAID FIRST GWEIGHT TO SAID FINAL POSITION, AND DETONATOR MEANS CONNECTED TO SAID OTHER END OF SAID SPRING AND MOVABLE TO AN ARMED POSITION AS A RESULT OF SPRING EXPANSION. 